CN104263985B - A kind of from the hard preparation method strengthening Cu-FeC composite - Google Patents

Abstract

The invention discloses a kind of preparation method from hard strengthening Cu FeC composite, the Fe C powder body of mix homogeneously and copper powder are carried out ball milling and mixes powder, be then passed through pre-stamped formation blank, blank through Overheating Treatment, obtains Cu FeC composite after hot pressed sintering.The present invention is from the hard preparation method strengthening Cu FeC composite, by carburizing in reduced iron powder during preparation Cu FeC composite, while not changing iron content, by FeC alloy is become martensite or bainite from austenite phase, largely improve hardness and the intensity of original Cu Fe composite, prepare the Cu FeC composite with high-strength high-conductivity.

Description

A kind of preparation method of self-hardening strengthened Cu-FeC composite material

technical field

The invention belongs to the technical field of composite material preparation, and in particular relates to a preparation method of self-hardening reinforced Cu-FeC composite material.

Background technique

Cu-Fe composite materials have comprehensive properties of high strength and high conductivity and can be widely used in industries such as microelectronics, electric power and machinery. It can also be applied to bases and electrodes of large-scale resistance welding machines, large-capacity turbogenerator rotor wedges, retaining ring materials, VLSI lead frames, overhead wires for high-speed rail transit, electronic countermeasures for national defense, radar, high-power Military microwave tubes, thermonuclear experimental reactor (ITER) divertor vertical target cooling fins and high pulse magnetic field conductor materials and other fields. However, while the existing Cu-Fe composite materials increase the strength by increasing the proportion of iron, they also have a great impact on the electrical conductivity of the material. Secondly, the use of general reduced iron powder to develop composite materials also has great limitations in strength.

With the continuous development of science and technology, Cu-Fe-Ag composite materials have been prepared by adding a certain amount of Ag to Cu-Fe composite materials at home and abroad. Although the performance of the material has been greatly improved, it has increased The production cost of materials is not conducive to the large-scale production and use of composite materials, so there is still a lot of room for improving the preparation method of Cu-Fe composite materials.

In order to obtain a Cu-Fe composite material with low cost and high strength and high conductivity, the present invention adopts the process of carburizing common reduced iron powder to obtain high-carbon iron powder, which is prepared by combining copper matrix and high-carbon iron powder. Hardened copper matrix composites. At present, there is no relevant report on the preparation method of the low-cost and high-performance Cu/FeC composite material mentioned in the present invention.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a self-hardening reinforced Cu-FeC composite material, which solves the problem of low strength and electrical conductivity of the existing Cu-Fe composite material.

The technical solution adopted in the present invention is a preparation method of self-hardening strengthened Cu-FeC composite material, which is to carry out ball milling and mixing of uniformly mixed Fe-C powder and copper powder, and then form a blank through pre-pressing, and the blank is heated After pressing and sintering, it is heat treated to obtain Cu-FeC composite material.

The present invention is also characterized in that,

The Fe-C powder is obtained by the following method: put iron powder and carbon black into a ball mill jar, add balls 40 times the total mass of the powder, put it into a high-purity graphite crucible after ball milling for 6 hours, Heating under the atmosphere to make Fe-C powder.

The mass percentage of carbon black in the Fe-C powder is 0-0.8 wt%, the grain size of the iron powder is 200 mesh, and the purity is 99.7%.

The method of ball milling Fe-C powder and copper powder is as follows: Weigh 12% Fe-C powder and 88% copper powder according to mass percentage, put Fe-C powder and copper powder into the ball mill tank, press 20-40 times of the total mass of all the powders are added into the balls, and the powders are mixed by ball milling for 12-24 hours to obtain Cu-FeC mixed powders.

The pre-pressing is to pre-press the Cu-FeC mixed powder through a cold press mold after sieving, the pressing pressure is 10-300KN, and the pressure is maintained for 30-120 seconds to form a blank.

Hot-pressing sintering is to put the blank formed by pre-pressing into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 950-1050°C, then perform hot-pressing under a pressure of 1.5-3MPa and keep it warm for 30-60min , When the temperature of the hot-press furnace is lowered to room temperature, the pressure is removed, and the surface of the blank is processed.

Heat treatment is to heat-treat the blank after hot pressing and sintering in a box-type heat treatment furnace. The quenching temperature is 727-880°C, hold for 20-60 minutes, and water-cooled quenching; then heat to 150-350°C, hold for 30-90 minutes for annealing, and air-cool.

The beneficial effect of the present invention is that, the preparation method of the self-hardening strengthened Cu-FeC composite material of the present invention, by carburizing the reduced iron powder in the process of preparing the Cu-FeC composite material, while not changing the iron content, by adding The FeC alloy transforms from austenite to martensite or bainite, which greatly improves the hardness and strength of the original Cu-Fe composite material, and prepares a Cu-FeC composite material with high strength and high conductivity. It provides a new idea for the study of such composite materials.

Description of drawings

Fig. 1 is the scanning electron microscope figure of Fe-C powder in embodiment 1;

The scanning electron micrograph of iron powder in Fig. 2 embodiment 1;

3 is a microstructure diagram of the Cu-FeC composite material prepared in Example 1.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The preparation method of the self-hardening strengthened Cu-FeC composite material of the present invention is to perform ball milling and mixing of uniformly mixed Fe-C powder and copper powder, and then pre-press to form a blank, and the blank is subjected to heat treatment after hot pressing and sintering to obtain Cu- FeC composites.

Specifically follow the steps below:

Step 1, weigh 0～0.8wt% carbon black according to the mass percentage respectively, and the rest is iron powder, the granularity of iron powder is 200 mesh, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press powder total 40 times of the mass is added into balls, ball milled for 6 hours, put into a high-purity graphite crucible, and heated in a hydrogen atmosphere at 300-1250°C to make Fe-C powder;

Step 2, weigh 12% of the Fe-C powder and 88% copper powder obtained in step 1 according to the mass percentage, and put the Fe-C powder and copper powder into the ball mill jar, and weigh 20-40% of the total mass of all powders. Doubling the balls and milling for 12-24 hours to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2, and then pre-pressing through a cold-pressing mold, the pressing pressure is 10-300KN, and the pressure is maintained for 30-120 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 950-1050°C, then perform hot pressing under a pressure of 1.5-3 MPa and keep it warm for 30-60 minutes, When the temperature of the hot pressing furnace is lowered to room temperature, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 727-880°C, keep warm for 20-60min, and water-cooled quenching; then heat to 150-350°C, keep warm for 30-90min and anneal, Cool in air to obtain Cu-FeC composite material.

The preparation method of the self-hardening strengthened Cu-FeC composite material of the present invention is by carburizing the reduced iron powder in the process of preparing the Cu-FeC composite material, while not changing the iron content, by changing the FeC alloy from the austenite phase It becomes martensite or bainite, which greatly improves the hardness and strength of the original Cu-Fe composite material, and prepares a Cu/FeC composite material with high strength and high conductivity. Provided new ideas.

Example 1

Step 1, take by weight 0.4wt% carbon black respectively by mass percentage, all the other are iron powder, the granularity of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill tank, press the powder total mass Add balls 40 times, ball mill for 6 hours, put into a high-purity graphite crucible, and heat at 500°C under a hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, put the Fe-C powder and copper powder into the ball mill jar, and add 20 times the total mass of all powders Grinding balls, performing 12h ball milling and mixing to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold pressing die, the pressing pressure is 10KN, and the pressure is maintained for 50 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 1025°C, then perform hot pressing under a pressure of 1.5 MPa and keep it warm for 60 minutes. When the temperature of the hot pressing furnace is When it is lowered to room temperature, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 780°C, hold for 20 minutes, and quench with water; then heat to 180°C, hold for 40 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 1 has a strength of 560 MPa and an electrical conductivity of 12.6 MS/m.

The scan diagram of the iron powder in Fig. 1 embodiment 1, it can be seen that the original Fe powder has coarse particles and rough surface with defects;

Fig. 2 is the scanning electron microscope picture of Fe-C powder in embodiment 1, the Fe-C powder prepared through step 1, its particle is fine;

Figure 3 is the microstructure of the Cu-FeC composite material prepared in Example 1. The black particles in Figure 3 are Fe-C phases, which are evenly distributed in the Cu matrix, and play a role of self-hardening after heat treatment.

Example 2

Step 1, take by weight 0.3wt% carbon black respectively by mass percentage, all the other are iron powder, the particle size of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press powder total mass Add balls 40 times, ball mill for 6 hours, put into a high-purity graphite crucible, and heat at 800°C under a hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, put the Fe-C powder and copper powder into the ball mill tank, and add 30 times the total mass of all powders Grinding balls, performing 18h ball milling to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold-pressing mold, the pressing pressure is 30KN, and the pressure is kept for 60 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 1040°C, then perform hot pressing under a pressure of 2 MPa and keep it warm for 40 minutes. When the temperature of the hot pressing furnace drops When the room temperature is reached, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 750°C, hold for 20 minutes, and quench with water; then heat to 150°C, hold for 40 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 2 has a strength of 540 MPa and an electrical conductivity of 12.8 MS/m.

Example 3

Step 1, take by weight 0.6wt% carbon black respectively by mass percentage, all the other are iron powder, the granularity of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press the powder total mass Add balls 40 times, put into high-purity graphite crucible after ball milling for 6 hours, and heat at 300℃ under hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, put the Fe-C powder and copper powder into the ball mill jar, and add 20 times the total mass of all powders Grinding the ball, and performing 24h ball milling to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold pressing die, the pressing pressure is 50KN, and the pressure is maintained for 40 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 1050°C, then perform hot pressing under a pressure of 2.5 MPa and keep it warm for 50 minutes. When the temperature of the hot pressing furnace When it is lowered to room temperature, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 840°C, hold for 35 minutes, and quench with water; then heat to 210°C, hold for 45 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 3 has a strength of 568 MPa and an electrical conductivity of 12.2 MS/m.

Example 4

Step 1, take by weight 0.8wt% carbon black respectively by mass percentage, all the other are iron powder, the granularity of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press the powder total mass Add balls 40 times, ball mill for 6 hours, put into a high-purity graphite crucible, and heat at 1250°C under a hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, and put the Fe-C powder and copper powder into the ball mill tank, adding 40 times the total mass of all powders Grinding the ball, and performing 24h ball milling to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold-pressing mold, the pressing pressure is 60KN, and the pressure is maintained for 30 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 1050°C, then perform hot pressing under a pressure of 3 MPa and keep it warm for 60 minutes. When the temperature of the hot pressing furnace drops When the room temperature is reached, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 860°C, hold for 40 minutes, and quench with water; then heat to 230°C, hold for 60 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 4 has a strength of 585 MPa and an electrical conductivity of 12.0 MS/m.

Example 5

Step 1, take by weight 0.1wt% carbon black respectively by mass percentage, all the other are iron powder, the granularity of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press the powder total mass Add balls 40 times, put into high-purity graphite crucible after ball milling for 6 hours, and heat at 1000℃ under hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, put the Fe-C powder and copper powder into the ball mill tank, and add 30 times the total mass of all powders Grinding balls, performing 15h ball milling to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold-pressing mold, the pressing pressure is 300KN, and the pressure is kept for 120 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 950°C, then perform hot pressing under a pressure of 2 MPa and keep it warm for 30 minutes. When the temperature of the hot pressing furnace drops When the room temperature is reached, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 727°C, hold for 60 minutes, and quench with water; then heat to 350°C, hold for 90 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 5 has a strength of 588 MPa and an electrical conductivity of 11.6 MS/m.

Example 6

Step 1, take by weight 0.2wt% carbon black respectively by mass percentage, all the other are iron powder, the granularity of iron powder is 200 orders, and purity is 99.7%, iron powder and carbon black are packed in the ball mill jar, press the powder total mass Add balls 40 times, put into high-purity graphite crucible after ball milling for 6 hours, and heat at 600°C under hydrogen atmosphere to make Fe-C powder;

Step 2: Weigh 12% of the Fe-C powder and 88% of the copper powder obtained in step 1 according to the mass percentage, and put the Fe-C powder and copper powder into the ball mill tank, adding 40 times the total mass of all powders Grinding the ball, and performing 20h ball milling to obtain Cu-FeC mixed powder;

Step 3, sieving the Cu-FeC mixed powder obtained in step 2 and then pre-compressing it through a cold pressing die, the pressing pressure is 100KN, and the pressure is maintained for 30 seconds to form a blank;

Step 4, put the blank formed in step 3 into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 1000°C, then perform hot pressing under a pressure of 2.5 MPa and keep it warm for 40 minutes. When the temperature of the hot pressing furnace When it is lowered to room temperature, the pressure is removed, and the surface of the blank is processed;

Step 5, heat-treat the blank after hot-pressing and sintering in step 4 in a box-type heat treatment furnace, the quenching temperature is 880°C, hold for 50 minutes, and quench with water; then heat to 300°C, hold for 30 minutes for annealing, and air-cool to obtain Cu-FeC composite Material.

After testing, the Cu-FeC composite material prepared in Example 6 has a strength of 535 MPa and an electrical conductivity of 12.3 MS/m.

Claims (4)

1. A preparation method for self-hardening reinforced Cu-FeC composite material, characterized in that, the uniformly mixed Fe-C powder and copper powder are mixed by ball milling, then pre-pressed to form a blank, and the blank is sintered by hot pressing After heat treatment, Cu-FeC composite material is obtained; Pre-pressing is to pre-press the Cu-FeC mixed powder through a cold press mold after sieving, the pressing pressure is 10-300kN, and the pressure is maintained for 30-120 seconds to form a blank; Hot-pressing sintering is to put the blank formed by pre-pressing into a high-purity graphite crucible, place it in an atmosphere-protected pressurized sintering furnace and heat it to 950-1050°C, then perform hot-pressing under a pressure of 1.5-3MPa and keep it warm for 30-60min , when the temperature of the hot-press furnace is lowered to room temperature, the pressure is removed, and the surface of the blank is processed; Heat treatment is to heat-treat the blank after hot pressing and sintering in a box-type heat treatment furnace. The quenching temperature is 727-880°C, hold for 20-60 minutes, and water-cooled quenching; then heat to 150-350°C, hold for 30-90 minutes for annealing, and air-cool. 2. the preparation method of self-hardening strengthened Cu-FeC composite material according to claim 1 is characterized in that, Fe-C powder obtains by following method: iron powder and carbon black are packed in the ball mill jar, press powder total 40 times the mass is added to balls, and after ball milling for 6 hours, put it into a high-purity graphite crucible, and heat it under a hydrogen atmosphere at 300-1250°C to make Fe-C powder. 3. the preparation method of self-hardening strengthened Cu-FeC composite material according to claim 2 is characterized in that, the mass percent of carbon black in Fe-C powder body is 0～0.8wt%, and the particle size of iron powder is 200 orders , with a purity of 99.7%. 4. the preparation method of self-hardening strengthened Cu-FeC composite material according to claim 1 is characterized in that, the mode of powder mixing of Fe-C powder body and copper powder ball mill is as follows: take 12% Fe- C powder, 88% copper powder, put Fe-C powder and copper powder into a ball mill tank, add grinding balls according to 20 to 40 times the total mass of all powders, and perform ball milling for 12 to 24 hours to obtain Cu-FeC Mix powder.